In recent years, semiconductor high-power elements such as a GaN-FET (Field Effect Transistor) as a power amplification element have come into widespread use. Due to advantages such as a long life, such semiconductor high-power elements have been increasingly applied also to a transmission system including an amplifier/oscillator constituted using a vacuum tube device. However, as compared with a vacuum tube device, the output power is relatively small by a semiconductor element alone, so that power combining is indispensable for a transmission device for a high-power application using a semiconductor.
There is an array antenna device as means for implementing a high-power transmission device using a semiconductor. Various configurations of array antenna devices have been proposed until now. For example, Japanese Patent No. 5377750 (PTD 1) discloses an array antenna device configured to combine transmission high-frequency signals combined from a plurality of (n) local oscillation signals. According to the array antenna device in PTD 1, the SN ratio can be improved by n times higher than that in the configuration in which the transmission high-frequency signal generated from a single local oscillation signal is amplified by n times.